(1) Field of the Invention
The present invention relates to a complex profile bar consisting of a metal profile bar coated with a metal foil.
The invention also relates to a method for manufacturing such a complex profile bar.
The invention also relates to a device for implementing this method.
The present invention falls within the field of the building ironmongery.
The invention relates in particular to the profile bars used as accessories in the finishing of the building.
These profile bars are in general intended to be used as accessories for the installation of floating parquet, or as junction elements between floor and/or wall elements, such threshold bars, nosings, plinths or the like.
Other applications relate to closing parts of the building: doors, windows, blinds, verandas, fences or the like, as well as all the fields in which profile bars are of an interest as safety or junction parts: electric ducts, tiling ends, or also as decoration elements.
(2) Description of the Prior Art
It is known to use profile bars made of aluminium alloy, or of plastic, even of wood, coated with paper or plastic films, on coating lines. These coatings allow a wide choice of decorations.
However, these profile bars, which are designed for domestic use, are poorly suited for intensive professional use.
The manufacture of metal profile bars, made of metals or of aluminium alloys, brass or the like, provides a first solution for this problem of strength. Nevertheless, such profile bars made of material with low surface hardness are sensitive to scratching, and their surface is quickly degraded, when they are subjected to intense traffic.
There is a strong market demand for stainless-steel profile bars, which would have, in addition to a perfect appearance, a good resistance both to corrosion, scratching and to impacts, and would meet the sanitary constraints specific to the hospital environments or also to the food-processing industry.
The manufacture of mass metal profile bars tried to meet this need. These profile bars are expensive because of the costs of material and the extrusion tools. In addition, the particular shapes of such profile bars include significant differences in cross-section as well as very small radii of curvature, even profile bars with sharp edges, which makes their manufacture by drawing very problematic. The too disparate internal tensions result into cracks or other defects, which make the profile bar unsuitable for its use. Finally, the manufacturing time for the tools does not allow reacting to a need of the market.
It has also be devised to apply a metal profile bar of a suitable strength against a structure such as another profile bar, in particular a metal profile bar, by screwing, welding, riveting or another mechanical fastening means of a high cost.
It should also be noted that the coating of a profile bar with a film on a coating line is a difficult operation, because of the multiplicity of technical problems: preparation of the surfaces, tension of the film, temperature, hygrometry, control of the quantity of adhesive and the shaping and application means, among others, and which are to be solved simultaneously, in order to avoid adherence or appearance defects, such as air bubbles, creasing, tear or the like, which make the product unsuitable for any use.
The specialist in the art, who has been faced for some twenty years with the market's need for profile bars with a hard metal surface, and because of the existing problems for coating with so-called easy-to-process films, has been dissuaded from any trying to continuously coat profile bars with a metal foil made of hard material having a sufficient thickness to meet the service-load stresses.
From BE 699 571 is known a complex metal-on-metal profile bar achieved by close adjustment. This does not guarantee a perfect adherence at all points. In addition, the method this document describes is applicable only to some very particular profiles of profile bars made of aluminium and including side openings, i.e. grooves in which a foil can be crimped, which considerably limits the field of application.
Another document, GB 2 037 626 A, contemplates to insert an adhesive, or a double-face adhesive tape between the profile bar and the foil. Here too, no guarantee of adherence is to be expected.
In short, the prior art only provides solutions in which the adherence of the foil to the profile bar is not, or badly, guaranteed, which is incompatible with applications in the field of building joinery, where the profile bars are subjected to high service-load stresses. It should be noted that due to lack of guarantee of adherence, no metal profile bar coated with a metal foil is offered on the market.